Seatback tilt adjustment mechanism

An adjustable mechanism for seats, primarily for motor vehicles, comprising

• a. a first bracket to be secured to one portion of said motor vehicle seat,
• b. a second bracket cooperating with said first bracket for being secured to a second portion of the motor vehicle seat,
• said first bracket forming an integral structure and comprising a gear ring of internal teeth and said second bracket also forming an integral structure and comprising a gear ring of internal teeth of the same diameter as the gear ring of the first bracket, with the number of teeth of the first gear ring and of the second gear ring, respectively, differing by a predetermined quantity,
• c. a raised portion on said first bracket,
• d. a recess in said second bracket,
• said recess corresponding to said raised portion of the first bracket, with said brackets thereby being capable of being monted for rotative motion in each other,
• e. at least one gear wheel having a substantially smaller diameter than said gear rings,
• said one gear wheel being movable in a planetary orbit inside of said gear rings and being mounted for meshing therewith,
• f. two cover plates for covering the two gear rings,
• one of said cover plates fitting into a corresponding recess of the first bracket and a second of said cover plates covering the second gear ring by enclosing a raised portion thereof, and
• g. a shaft comprising the axis of rotation of said gear wheel penetrating said cover plates for making said plates rotative as a unit,
• whereby the two brackets are rotative with respect to each other for providing continuous adjustment of the seat back with regard to the base portion of the seat.